package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    private Connector connectorPojo = new Connector();

    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
        String appBase = loadServer();


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize =50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(connectorPojo.getPort());
        System.out.println("=====>>>Minicat start on port：" + connectorPojo.getPort());

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/



        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while(true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,contextMap,appBase);
            requestProcessor.start();
//            threadPoolExecutor.execute(requestProcessor);
        }



    }

    private Map<String,Context> contextMap = new HashMap<>();

    /**
     * 加载解析server.xml，初始化miniCat
     */
    private String loadServer(){
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        String appBase="";


        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            Element service = (Element) rootElement.selectSingleNode("Service");
            Element connector = (Element)service.selectSingleNode("Connector");
            int port = Integer.parseInt(connector.attributeValue("port"));

            Element engine = (Element) connector.selectSingleNode("Engine");
            Element host = (Element) engine.selectSingleNode("Host");
            String hostName = host.attributeValue("name");
            appBase = host.attributeValue("appBase");

            connectorPojo.setHost(hostName);
            connectorPojo.setPort(port);
            connectorPojo.setAppBase(appBase);

            List<Element> selectNodes = engine.selectNodes("//Context");
            for (Element e :selectNodes) {
                Context context = new Context();

                String projectName = e.attributeValue("path");
                context.setProjectName(projectName);


                Map<String,HttpServlet> servletMap = new HashMap<String,HttpServlet>();
                loadServlet(servletMap,appBase+File.separator+projectName);

                context.setServletMap(servletMap);

                contextMap.put(context.getProjectName(),context);

            }


        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return appBase;
    }



    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet(Map<String,HttpServlet> servletMap,String appBase) {
//        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");


        try {
            InputStream resourceAsStream = new FileInputStream(appBase+ File.separator+"web.xml");
            SAXReader saxReader = new SAXReader();


            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element =  selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();

                MyClassLoader loader = new MyClassLoader();
                Class<?> aClass = loader.findClass("file:///"+appBase,"server.LagouServlet");



                servletMap.put(urlPattern, (HttpServlet)aClass.newInstance());


                System.out.printf("=======");

            }



        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }

    }


    /**
     * Minicat 的程序启动入口
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {


            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
